Mobile systems exist that allow for both voice communication (e.g., a mobile telephone) and general data transfer (e.g., mobile Internet Protocol). In addition, cellular radio communications systems provide paging/access, or control, channels for carrying call-setup messages between base stations and mobile stations. These functions can be combined in a single device, but must be functionally separated to take maximal advantage of all functions. This is because TDMA cellular traffic operates in a buffer and burst, or discontinuous-transmission, mode. That is, each mobile station transmits and receives only during its assigned time slots. At full rate, for example, a mobile station might transmit during slot 1, receive during it) slot 2, idle during slot 3, transmit during slot 4, receive during slot 5, and idle during slot 6, and then repeat the cycle during succeeding TDMA frames. Thus, while a mobile system is carrying voice data over a traffic channel, data can be sent in either direction.
One defining feature of all prior art systems is that the prior art systems contain, on the one hand, traffic channels to carry traffic data, and on the other hand, overhead channels dedicated to the functional aspects of a mobile-station to base-station interaction. For example, hand shaking occurs over these overhead channels. Because of bandwidth and other functional constraints, no traffic data is saved over the overhead channels, also known as digital control channels (DCCH). For example, general browsing is conducted over a wireless Internet protocol (IP) session, at which time the device essentially is dedicated to data service.
Much of the traffic data carried by the mobile system is very short-burst data such as e-mail. Because this data can be transmitted in a relatively short burst, however, the time typically taken by the mobile system to set up a communication channel to transmit the burst is greater than the duration of the burst. This inefficiency, based on the short duration of the burst, is rampant among these types of systems. It is possible to use the DCCH for this sort of short-burst data, but in the IS-136 TDMA environment, the use of an IS-136 digital control channel (DCCH) for interactive data services presents several problems. First, the latency of the channel is unacceptable for general network-browsing functionality, and second, the use of the DCCH for this purpose could impact the quality of the voice service provided by the network. Thus, any use of the DCCH must be limited to use by short-burst data that can tolerate a high-latency connection.
Thus, it is desirable to queue application-service requests in the background of general wireless use, over the DCCH, without the invocation of a full wireless IP session that would allow the operation of functions without forcing the user into the browser mode of the device.